DES MOINES, Wash. (CBS Seattle) — A South King County father is accused of lacing his children’s cookies with methamphetamines to discredit his ex-wife before an upcoming custody hearing.

The Seattle Post Intelligencer reports that Chad Holm, 37, made cookies with meth in them so his kids would give them to their mother. The children, aged 5 and 7, subsequently tested positive for the drug.

Des Moines Police Department officials say the ex-wife, who was a previous meth user with Holm, tested positive last September after being clean for a year. KBOI-TV reports that the 7-year-old boy brought cookies Holm made to give to her. When she and her 5-year-old son ate them, she told police that they “tasted terrible” and threw them away.

The ex-wife pointed the finger at Holm and his current girlfriend for sabotaging the cookies with meth.

Despite denials, police say Holm failed a recent drug test and that he forged those results to the court in an attempt to show he was clean.

Holm has been charged with second-degree perjury but has yet to be charged for allegedly drugging his kids and ex-wife due to lack of evidence.

“We are unable to file charges at this time against Mr. Holm or his girlfriend for providing the methamphetamine to the children because we cannot prove the chain of custody of how the meth was placed in the cookies, who made the cookies and who, when, where or how the meth was given to the children,” Ian Goodhew, spokesman for the King County Prosecutor’s Office, told the Post Intelligencer.